1. Field of the Invention
The present invention relates to an information processor.
2. Description of the Related Art
In an information processor such as a digital copier and a Multifunction Product (MFP) that processes, for example, image data, a Peripheral Component Interconnect (PCI) bus is used as an interface between devices as shown in FIGS. 34 and 35. However, due to racing, skew, etc., a parallel PCI bus cannot provide a high data transfer rate sufficient for use in an image-forming device required to operate at a high speed and also to produce high quality images. Therefore, high-speed serial interfaces such as Institute of Electrical and Electronics Engineers (IEEE) 1394 interface and Universal Serial Bus (USB) are now studied to be used instead of the parallel PCI bus. For example, Japanese Patent Application Laid-Open No. 2001-016382 has proposed a technique using a high-speed serial interface such as the IEEE 1394 interface or the USB as an internal interface.
As another high-speed serial interface, the PCI Express (trademark), which is a successive version of the PCI bus, has been proposed and is now available for the practical use. Reference may be had to, for example, an article by Takashi Satomi “Outline of the PCI Express standard” taken from journal “Interface”, July 2003. A PCI Express system is configured as a data communications network with a tree structure, including a root complex, a switch, and devices as shown in FIG. 1 of the article.
Information processors such as the MFP have an option slot that allows for a variety of functions according to necessity in addition to the basic components including a scanner and a plotter. More specifically, as shown in FIG. 34, optional boards for all necessary functions are installed in the option slot in, for example, an internal bus of the information processor. A plurality of information processors each having a different optional board can be used to enable a user to select the suitable one according to the purpose.
However, if optional boards for all necessary functions are installed in each information processor as shown in FIG. 34, the information processor requires higher costs.
To use a plurality of information processors each having a different optional board, the user is forced to conduct cumbersome operations, such as walking to a place where installed is an information processor with an optional board having a function which the user needs, moving each information processor to another place, or installing a plurality of drivers for connecting a computer and switching the drivers.
In addition, the information processor like the MFP that includes, for example, a scanner, a plotter, and a controller further includes a storing device such as a memory or a Hard Disk Drive (HDD) for temporarily storing a large amount of image data. The storing device is used for storing backup data for jam recovery on printing by the plotter, and image data for a plurality of pages on integrated printing, electronic sorting, or producing a composite image.
The larger the capacity of the storing device, the more image data the image processing device can process at a time. In other words, by increasing the capacity of the storing device, the performance of the information processor, such as integrated printing, can be enhanced. Therefore, to acquire a higher processing performance, an extra HDD or memory is added to an information processor.
However, an increase in the capacity of the storing device by adding a memory and a HDD results in higher cost of the information processor. Besides, the number of memories which can be added to one information processor is limited depending on the number of expansion slots available or a free space.